The present disclosure is related to wellbore servicing tools used in the oil and gas industry and, more particularly, to an improved coupling for cement heads.
During completion of oil and gas wells, cement is often used to solidify a well casing within the newly drilled wellbore. To accomplish this, cement slurry is first pumped through the inner bore of the well casing and either out its distal end or through one or more ports defined in the well casing at predetermined locations. Cement slurry exits the well casing into the annulus formed between the well casing and the wellbore, and is then pumped back up toward the surface within the annulus. Once the cement hardens, it forms a seal between the well casing and the wellbore to protect oil producing zones and non-oil producing zones from contamination. In addition, the cement bonds the casing to the surrounding rock formation, thereby providing support and strength to the casing and also preventing blowouts and protecting the casing from corrosion.
Prior to cementing, the wellbore and the well casing are typically filled with drilling fluid or mud. A cementing plug is then pumped ahead of the cement slurry in order to prevent mixing of the drilling mud already disposed within the wellbore with the cement slurry. When the cementing plug reaches a collar or shoulder stop arranged within the casing at a predetermined location, the hydraulic pressure of the cement slurry ruptures the plug and enables the cement slurry to pass through the plug and then through either the distal end of the casing or the side ports and into the annulus. Subsequently, another cementing plug is pumped down the casing to prevent mixing of the cement slurry with additional drilling mud that will be pumped into the casing following the cement slurry. When the top cementing plug lands on the collar or stop shoulder, the pumping of the cement slurry ceases.
To perform the aforementioned cementing operations, a cement head or cementing head is usually employed. The cement head is arranged at the surface of the wellbore and the cementing plugs are held within the cement head until the cementing operation requires their deployment. The cement head must be able to withstand enormous tensile forces along its entire length attributable to the overall weight of the work string coupled to the cement head and extended into the wellbore. In some cases, the cement head and its various internal connections may be required to bear several million pounds of tensile force.